I have them on my doors, I'm going to keep them, but if you want me to send you the dimensions so that you can create them, I'm happy to take some measurements.

(and I suppose if you really want them, I can probably part with them for outrageous money )

 

Measurements would be great! I'm assuming that the speaker underneath is a 4x6? I'll pm you.

 

Here's what I got (inches):
Overall width is 7 1/4, height is 3 5/8, speaker grill is 6 x 3 1/2, depth is 1 1/4 and the little notches are 1/2 inch wide.

Also picture of the backside, the speaker doesn't match what you have in the list (Phillips 25W). It is neither Phillips nor 25W, but the exterior appearance of the speaker box certainly seems to match that diagram. No idea if a previous owner swapped the speakers, but the back of that speaker sure looks 1980s to me, so if they did swap speakers it must have been pretty early in the car's life. The grill and the speaker are integrated, so I think it may have just been a different OEM. My GTV-6 is a 1985 if it helps.

Anyway, happy to help with anything else if I can.

 

Also found this post:

https://www.alfabb.com/threads/where-to-find-gtv6-oem-speakers.164307/

Which appears to (mostly) confirm my measurements.