One of my favorite commemoratives is Stone Mountain. I have two (Slabbed), one MS-64, the other AU-58. Thanks for sharing yours, good luck with your decision.
You might consider sending it to a third-party service that is less expensive than the "big boys." I would recommend ANACS.
Great feedback everyone. I have never had a coin slabbed and I think it will stay that way for awhile.
That's generally not an either or grade you would see. 58s are usually 63s or better that have friction. 60s are basically one thing away from being a details coin.
A quick check on ebay shows this coin in similar condition and raw selling for between $50 and $75. Same coin graded MS63 is about $125. If you think this coin would grade at 63 or better, I think it's probably worth submitting. But it seems you think it would grade 60 or lower, so probably not worth grading.
@John Johnson Thanks for the feedback. After collecting for over 70 years and never considering slabs at all, I think this ended up being an exercise to reaffirm my commitment to using eye appeal only. My friends here are great. I understand the complexity of the TPG process a lot better.
As I've said on here before, almost all of my coins are certified. The reason is for my heirs, so whoever they try to sell them to won't claim they're a lower grade than they really are. Also, I like the slabs for long-term storage.