Panther V Engine Cooling Fan Cover Castings Questions

I need information about Panther V model D vs. model A cooling fan cover castings.

An example of a resin replacement for the early D model shown here:

http://ipmslondon.ca/old%20site/ipmslondon.tripod.com/armourreviews/id23.html

or on a Panther A in restoration

and this type as found on the 1972 vintage Tamiya 1/25 Panther A kit:

photo of the Camp Borden, Ontario, Canada by Jean-Michel Cyr

http://www.toadmanstankpictures.com/panther_ausf_a_borden_40.jpg

Unfortunately, I have not yet been able to determine via research:

the approximate year the fan cover styles changed ( or approximate hull production run-if recrods still exisit) as well as

what each style is called amoung armor modeling groups?

Is anyone able to point to provide information for my querry?

My small number of books only provide photos and 3 view drawings but no other information.