Dash Insert for Radio 62 GMC

[captnubby]

Hello, new to the group, first post. I have a 1962 GMC fleetside I recently purchased for my first restoration project. Someone has cut up the dash and doors and installed a modern radio and 6x9 speakers. I have seen inserts for the radio area on ebay and LMC as well. My question is has anybody used these before? Without looking at them in hand it is hard to figure out how they mount up to original dash. Is it a bolt on overlay type fit or a cut out and weld in type fit?

Thanks, Dean