I have done both... to me it just depends. I have put work into horns that I knew would cost me more than I would recoup selling the horn but they were going to kids and I wanted them to have a nice trumpet. If I do leave the dents in it's because I am selling the horn off cheap as in $75-125 cheap... possibly an eBay unload for whatever it's going to go for.
Your horn sounds like a nice one so I would probably have the dents taken out.
My Holton 47 is going to be a deal for someone because I put over 275 in it on a restore ... that and what I paid for it will probably be a losing prop for me. I just thought it was too neat of a horn to be not played.