A Few Minor Questions about my 72 K5

[Dclassen]

I purchased some bolts to bolt down my backseat i believe they were 1/2"x1 1/2" and they fit to hold the back of the seat down but they wont thread into the front holes. Any ideas? They go in and seem like they may work but then just wont get in there. after awhile and pop out. Are these different size bolts needed for the front? I wouldnt think so. Im gonna pull the carpet tomorrow anyway just wondering if anyone knew off the top of their heads.

[pound41]

I think they are a fine thread