Correct .. what you work on today generally needs to meet today's rules. In this instance of fittings, I cannot see the 'maintenance' principles applying; it's not like you'ld have to pull a new wire!
Though, I must confess to being something of a hypocrite as to these newer fittings. They've been out for over five years - and I have yet to see one, let alone install one. Bridgeport, T&B, etal., seem quite happy to continue making the older style, and I'm not even sure the local parts houses have the newer ones on the shelf. Nor does it seem that the AHJ's are looking for them; that Reno is in the "desert" may be 'why.'