According to Anders Ditlev Clausager in "Original MGA" (page 92) there are two types of ash trays for the MGA. If you look at the ash tray as pictured in the parts list, it seems that the curvature at the front of the tray is higher than at the rear. The fixing screws are on the outside of the bottom flange (photo taken from "Original MGA" by Anders Ditlev Clausager)
Ashtray as pictured in the MGA Service Parts list AKD1215 for the A1600. The part number is AHH 5539
The pictures on the right and below are from my own MGA. It has the ash tray with the later part number AHH 7061. It looks like the curvature of the tray has the same height at front and rear. It also has a the fixing screws on the inside of the tray
I found this on one at an autojumble. It was exactly the same as the original ashtray, only the lid was black instead of chromed and it had a black crackle finish. Could this one be for an MGB?
A period aftermarket ash tray was made by the Jepco Manufacturing Co. in North Hollywood, California. They are extremely rare, how many are still around is unknown, but Rick Brown, who owns this one, has only seen six so far (photo's: Rick Brown)