Could my chinchilla be lonely?

i have a chinchilla that i had for 2 and a half years and i don't know how old he is (Chino). he has always been alone even with his previous owner. he never had a mate to chill with. but i was thinking that he may be lonely. my girlfriend also has a chin named Tiki whose about a year old now i am assuming (our chins are rescued therefore we don't know the exact ages). im trying to figure out whether or not to introduce them because of the age difference, if they will mate, different diets, and temperaments, can you house 2 chins that are different gender together? do i have to get one fixed i i don't want kips? which gender will be more safe for the chin to be fixed? do they need permanently separate fixtures? I need answers