1971 GMC K20 emergency brake.

[Ol Blue K20]

When I replaced the frame on Blue. I bought a frame off craigslist and was told it's a 72 GMC. It was a roller K20 with factory front hook holes which was a clue to the 71-72 vintage. But long story short, no partial VIN in either spot..

[52napco]

Pretty sure 72 was only year all got tow hook holes.....could be wrong but I'm 90%

[57taskforce]

I believe your correct about the hook holes, my K20 has them with no mention of hooks on the spid.