Here are pictures of an original factory aluminum hardtop made by Vanden Plas, nicely restored, taken at UML Summer Party Reunion in August 2004. (Click for larger pictures).


Built to be light weight, it has aluminum shell and plastic windows. The fabric interior liner looks substantial, but is in fact minimal and uninsulated. The tubing struts inside the window are structural (flattened to a "C" shape cross section). Rubber seals all around do a good job (assuming they are properly installed). Wing bolts at the front cormers attach to the windscreen same as the rag top. "L" brackets at the sides use "J" bolts to attach to the rag top frame mounting brackets on the body aft of the doors. All aluminum hardtops were built with off white interior liner and black painted exterior. Many have since been painted other colors, most commonly to match the main body color of the car.

Find Service Parts List for Aluminum Hardtop here.
From MGA 1500 Service Parts List, page R.39 and plate RQ.