Is there such a thing as 80% Garand receivers?

[Kayser]

1911's, AR15's, AK's - ho hum. Does anyone make 80% Garand receivers?

[Dfariswheel]

No.
The M1 receiver is an extraordinarily complex item, and requires some very sophisticated heat treating once finished.

The number of people capable and equipped to finish an 80% M1 receiver is so small, it's just not economically sound to bother making an 80% for sale.