Ok, I have two students who were given pistols (old pistols - 32SW and such) by their family while in another state. Then I have one student who was given a few revolvers back in the 70's. These students are going for their pistol permits through my class. They brought up the question of is this going to be a problem when carrying and or selling. I don't see the issue with carrying though selling I'm not sure of.

I believe these were given to them when they were over 21. I'll have to ask next class. Two students in their late 40's and the other in his 60's. Would there be a question by the state or officer (if stopped for some stupid reason and they say they are carrying) if they had these pistols or revolvers on them or even selling them?

There is no statutory requirement for one moving into the state to notify the state of their firearms. SLFU may "recommend" one do so but it is absolutely not required. Law enforcement and others are well aware the state's weapons registry is full or errors and will not contain all the firearms people legally and lawfully possessed. It is up the student to ensure they legally possessed the handgun/firearm when they obtained that firearm (however it was obtained). Other states may have different rules on how handguns get transferred. I think some states indicate a person 18 or older can obtain a handgun.

Not sure how accurate the following is from usconcealedcarry.com, but it has some links to federal laws:
Federal Minimum Age to Purchase and Possess Handguns

We don't presently have a registration system like New York has, so that's not an issue.

There are a lot of people in Connecticut who own guns that are not in the state's database (e.g. because they purchased them out of state, antiques, the state lost track of the records, the state entered information incorrectly in their database, etc...). It's also not unheard of for people who own pistols to be applying for "new" permits (e.g. previously had a permit and it expired, bought pistols on a 14 day wait before that handgun safety act required a permit/COE, retired LEO who didn't previously have a permit, moved into state with guns, has/d an eligibility certificate and wants to take their pistols out of the house, and several other reasons).  In general, if it's not on the database, they wouldn't know that the applicant had it. There are some towns that do ask for an inventory of applicant's weapons as part of the application process (something that is outside the state application).

I wouldn't have any concerns about lawfully carrying a pistol that isn't in the database, though sometimes it may raise questions. At one point there was a video of somebody open-carrying in Hartford (back when open carry was legal) that had a gun that wasn't associated with him on the database that did get a couple of extra questions about it). There have also been a couple of appeals hearings in which the state has attempted to use information of guns coming back to others as a way to try to create negative inference as well.

If they do ever try to sell, SLFU will run the serial number during the authorization process. No problems unless it's a serial number that has been reported stolen.