They’re a minefield. So the Bachmann 37/4 is perfect for any 37/4 pre-DRS. Those overhauled by HNRC for DRS got the plates side windows and reinforced windscreens and LED taillights - 402, 405, 409, 419 and 425.This is the spec that AS have chosen for their initial 37/4 offering so reusing them for other locos is difficult if you’re a rivet counter like me 🤣
401, 407, 422 and 424/558 have the LED taillights and reinforced windscreens but not the plated side windows. That means you can model these from AS 37422 when it comes out.
With some work the Bachmann 37/4 model is perfect for various 37/4, 37/5 and 37/7 models pre 2000, and as mentioned a base for 37800 as well.
Of course Bachmann have announced 37175 in Colas which should have the reinforced windscreens so I’m looking forward to seeing that.