I'll wade in and try not to be too negative and hope I don't sound narcissistic....
My first two 'p/t retirement jobs' were at two different LGS's. Worked consecutively, due to a move of about 25 miles at the time.
What I'll call the 'honeymoon period' was really enjoyable. Learning the store and stock, procedures, getting to know other staff, and getting to know some of the interesting regular customers and/or hang-arounds.
At that first store, sales/counter guys did no paperwork. All 4473's and actual sales transactions were handled by owner's elderly mother and his daughter and perhaps one other girl at the cash register.
Then - the 'panic buying' episodes came along.
O M G - the damn phone would NOT stop ringing. Callers and prospective 'buyers' on the phone sounded like they'd just run the 880M race and had almost zero knowledge about what they wanted but wanted it NOW.
This is all while the store was at maximum Fire Code capacity for customers. I sold AR's priced at close to $2000 to people who had to be shown a .223/5.56 cartridge. They'd never seen one.
Actually recall having my sleeve grabbed while enroute to the bathroom for a rare break. Panicked customer talking about 'C-mags', or 'Beta-mags' or some mess.
Fast-forwarding to the next LGS after our move....
This one, smaller, but also an indoor range. Very busy.
A couple more panic-buying episodes. Same thing with the phone which would ring continuously ALL day. Store so crowded it was shuffle-room only. And, we're supposed to keep an eye on the range through the Lexan windows also. Impossible.
Both locations shared the commonality of being family owned with various members of the family being employed there.
That in itself proved very problematic.
At such a location, no matter what you do or how much you put into the job to go the extra mile, and no matter how knowledgeable and experienced you are, guess what you are NOT?
You are not family.
Not regarded as anything beyond a hired clerk that will drift in and later be gone and they'll be hiring another body to take your place.
And there's no real impetus to actually PAY for your knowledge and experience. They just need someone who knows enough to make the SALE, as that's what's really important.
Glad I did it, valuable experience. Met some great people. Acquired some great guns (S&W's) as both places handled estates regularly.
But now count myself as having suffered 'Retail Burn-out'.
My most recent 'retirement job' was Security Contracting outside CONUS.
Much less stressful.
I'd say give it a try - enjoy the enjoyable parts and keep the whole thing in perspective. If it's family owned, always remember you're not family and keep expectations low.
Good luck.