Every weapon ever made has a disassembly process, handguns are no exception. Glocks can be takendown to it's 37 or so components, Rugers, Browing HPs, Berettas any pistol and even revolvers can be disassembled, side plates removed, trigger parts taken out....
Are ya looking for a list, sheesh that's way to much to type.....we're talking thousands, if it it was made, it has a disassembly procedure.
American Rifleman, mag distributed by the NRA w/ your subscription, (should ya chose it, or the American Hunter or American Guardian) and on a monthly basis shows a disassembly diagram of rifles and pistols, from those made in the 1800's to current production handguns and rifles.
Not certain why you'd not be aware of this, or fall for such BS by a dealer/gunsmith, whose obviously just preying on your naivete, suggest ya find another one, as this is a sure sign of one to avoid..... "Only Colts can be disassembled", not hardly........
Mike