For comparison my first ‘propper’ MTB had alex rims (XC19?), when they wore out I ‘upgraded’ to mavic 517’s (the then top end v-brake rim) and they were heavier!
My Pitch had alex rims OEM, again, considerably lighter than the Mavic’s I replaced them with.
Maybe not Stans light, but then they’ve not got eyelets, the OEM stans with eyelets are pretty much mavic weights.
Have they sorted a shimano 11 speed cassette body yet?
Hope RS hubs are the new 11s hubs, not clear if the frehubs are compatible though, they’re the new 40t ratchet ones.