Hard to say. I would need to look up component prices for a few years prior to my birth, and it would take me a few minutes to find that archive of 70s Radio Shack catalogs again - though I believe it was actually posted here, so. Of course anyone serious enough to be building an entire computer in those days, brilliant keyboard hack and all, probably wouldn't be sourcing a jellybean part like 1N400x signal diodes one by each...