Late dash pads have slightly different dimensions to accept the side vents. Opening for glove boxes x is different. Vinyl grain is slightly different.
I have a couple early dashes and one or two late ones sitting on a shelf for future builds. One of the early 4’s I bought was very rusty but an almost perfect interior. It was worth it just for the upper and lower dash. The repos are very nice but just like recovering a steering wheel, never the same as original.
I had a reproduction 914 dash but sold it to Gaswerks for their gold GT build.

I recently purchased a Paint and Interior binder with original factory pages for the various choices. For many year I had pages for 1970 through 1973 mostly complete. This purchase included 1975 & 1976, so I still have to look for the 1974 pages. Any leads appreciated. I do have some spare pages for 1972 and or 1973. The binder also includes 911 pages up to 1977, but again, 1974 is missing.
This has allowed me to update post 144 above for a nearly complete list of all codes used from 1970 through 1976. A little surprise was the tartan choice changes for 1976.
As always, any errors or omissions should be brought to my attention.

Interestingly even though there is a page for carpet fabric, nowhere is there a matrix that defines which carpet "color" is /would be matched with which seat color/material?