I can't speak from personal experience with Tinder, but it is absolutely possible if not likely that they send out advertising emails. Especially if he jsut deleted the app and didn't suspend/deactivate his account.

Since it's specifically Tinder gold that's being advertised, I would guess that it's an ad meant to pull dormant users back in.

"We haven't seen you on Tinder in a while. Here's a free 2 weeks of gold to get you back in dating pool!" Etc...

I wouldn't worry about it at all if he's given you no other reason to worry.