I will start you off with the "Holy Cow" factor. We know the original factory produced aluminum hardtop for the MGA is quite rare, and also in high demand. The value of a nice one can be quite high, but this might be the record. On July 25, 2004, an original aluminum hardtop for the MGA sold on eBay for $5,205.99. For as long as the link lasts, you may view the eBay auction page at:

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=2484941993
The auction photos are posted here by permission of the seller.

In a parallel auction ending one day later, from a different seller, a pair of side curtains of proper style for use with an MGA hardtop sold for $524.00. These were new and never used still in original packaging BMC part number AHH 5984 original style side curtains (1970's purchase) specifically built for use with the hardtop, noted because there are no rubber seals on the top and back edges of the frame. From the style of the bottom rubber seal, it appears these side curtains were intended for use with the later factory type fibreglass hardtop. For as long as this link lasts, you may view the eBay auction page at:

The factory aluminum hardtop (picture at right) was manufactured from June 1956 to June 1960 by Vanden Plas, a BMC subsidiary, with a reported 1450 units produced. The factory fiberglass hardtop (picture below) made by Universal Laminations and apparently much cheaper to produce, was introduced with the start of the MGA 1600 production in May 1959. As such, both aluminum and fiberglass units were in production at the same time for about 14 months.

Aside from the material, the styling around the back was somewhat different, and I believe it was always vinyl covered (on the outside). I presume it was intended by the factory that the later fiberglass top should be supplied (when the option was requested) for the 1600 model cars. So if you're thinking period correct for concours show, the aluminum top would be original for the 1500 and aftermarket for the 1600, while the fiberglass top would be original for the 1600 and aftermarket for the 1500.

It also appears that many of the "left over" aluminum hardtops were factory installed on the Deluxe roadster cars (24 tops or 34% of 1600 Deluxe roadsters, and 19 tops or 7% of the Mk II Deluxe roadsters). From factory records of rag top colors, these cars seem to have had both ragtop and hardtop. Only 5 cars or 2.8% of Twin Cam roadsters were fitted at the factory with a hard top and 100% of these did NOT have a soft top. Those 5 Twin Cams were the censecutively built 1960 MGA Twin Cam Sebring cars, 4 going to Sebring, and the Canadian copy (which never raced at Sebring).

Conclusion from this is that the aluminum top is the correct factory optional accessory for Twin Cams (when rarely installed), and for all 1600 Deluxes and early MK II Deluxes (as well as all 1500s). But all 1600 (not Deluxe) roadsters would use the fiberglass accessory top, and perhaps also some late production 1600 MK II Deluxe cars. Also if you bought a hardtop from the MG dealer after introduction of the MGA 1600, it would most likely have been a fibreglass top (even if you did drive a Twin Cam or Deluxe car).

It may bear noting that the MGA Coupe was introduced in Septemper 1956, three months after the first bolt-on hardtop. So the hardtop was NOT a reaction to the fact that the Coupe would go 3 MPH faster on the racetrack because of better aerodynamics. Perhaps the Coupe was a natural follow up to the styling of the first bolt-on hardtop, having a very similar roof line (but different rear glass arrangement).

There were some additional aftermarket fiberglass hardtops made by other companies, particularly in the USA where the largest number of MGA were resident. The first MGA I bought in 1968 came with a fiberglass hardtop attached. It was styled similar to the factory fiberglass hardtop, but had no internal or external fabric coverings and didn't fit to the body very well at the back.

For restoration informaiton and parts sources, see article TT-130.

More information and photos for MGA hardtops can be found at:
MGA Hardtop Group (Yahoo Groups)