Pentaprism glass block Nikkormat FTN/FT3 interchangeable?

I need to replace the glass pentaprism block in a Nikkormat FT3.
I was thinking of acquiring a cheap "parts" Nikkormat FTN online purely for the pentaprism block - can anyone tell me whether the pentaprism glass blocks are identical/interchangeable between these cameras?

Thanks, P

The Nikkormat FTN, FT2 and FT3 all use the same part number for the prism.

If the glass is OK but the silvering has deteriorated, have you considered restoring the old prism using a paint such as this:
https://www.rustoleum.com/product-catalog/consumer-brands/specialty/mirror-effect/

Mamiya_Repair said:

The Nikkormat FTN, FT2 and FT3 all use the same part number for the prism.

Click to expand...

Great, thank you!

4season said:

If the glass is OK but the silvering has deteriorated, have you considered restoring the old prism using a paint such as this:
https://www.rustoleum.com/product-catalog/consumer-brands/specialty/mirror-effect/

Click to expand...

Thanks for your response. In general terms the glass seems very good, no de-silvering or corrosion. The problem seems to be black fungal growth actually inside the block as if something is growing in between elements of the pentaprism block. It looks like the prism is built in multiple sections.
I've uploaded a quick phone snap of the black mass growing inside, not a great image but I think enough to get the gist.
I've never seen anything like this before - has anyone else?

Its also a mm smaller than the F eye level prism and fits nicely. I bought FT for that purpose, was the cheapest option.