Pre-resto Frame Straightening

[70']

Hi all, new to the board but no stranger to a wrench. I'm just getting ready to start a frame off of my 70 chevy short bed 4X4. I bought the truck a few years ago with the purpose of a full frame off restoration in mind. the truck has not ran since I bought it, so I have never "Driven" it other than winching it on and off the trailer to get it home. I am planning to start the tear down this weekend to get the frame off for paint and the thought has stuck me as to whether or not I should just go ahead and have the frame checked/straightened prior to paint just to make sure. I would hate to get the truck perfect then take it for its maiden voyage just to find out the frame is bent. I have no reason to suspect there is a problem, but also no evidence of there not being an issue either. What are your thoughts? Also, can they put a completly torn down frame in a straightener or should I do it while the truck is still whole prior to disassembly?