Need a little help and some add-vice.

[TJ's Chevy]

Ok...So alot of you guys know about my 64 C-20 I got awhile ago. 292 I6 with 4 speed....there is a mystery to remain...Is it the original engine..or is it a crate engine. It originally was a 3 speed column shift and someone changed it to an SM465...the 292 had some stuff done to it...painted blue...head gasket change out to felpro blue. I'm not sure if anything else was done...heck...the engine coulda been rebuilt. One member here warned me about a possible .030 overbore done to it....So my question is...is there a way to tell if that was the original engine? Here are the numbers.

Conveyor belt 2. C24 4 3 AM/PM 3851659 GM
5

As much as an I6 guru as I am I've never actually taken it to consideration that this engine coulda been rebuilt or had mods done to it before I got it...its obvious the engine was either pulled and painted...or bought as a crate engine and painted. but, I don't know fer sure....I'm planing on hot rodding this engine and want to bore it .040 over. Is there any way to tell if the engine has been bored over in the past with out having a machinist measure it? lol I'm gonna have him do that anyhow...but just curious. Thanks guys.