What do you mean by weird/archaic?
Most of it looks pretty realistic, US Army surplus that is handed down is a pretty massive part of modern SWAT arsenals, although this varies from station to station since some are better funded than others. I watched it again and I don't spot anything myself other than what appears to be an AR-18 at 6:15, but I don't mind more guns since I love nothing more than a large selection of obscure and highly detailed realistic firearms. I think I also spotted what appeared to be a SCAR-L which isn't commonly known to be in SWAT arsenals.
If that actually is a AR-18 and I am not mistaken, I'm damn surprised. Whoever is selecting firearms is clearly someone who loves obscure guns like I do. I mean, the Calico tipped me off early there.
But yeah, no, most of it appears pretty bread and butter to me. MP5s, M4s, M16s, M1014s, UMPs, Glocks and 1911s. As I previously said the AR-18 and SCAR-L(?) are the only odd ones out.