When I have been playing Brighton Mainline, the 377's have no pantograph, however in real life there is pantographs on the 377. In the cab they don't have the AC like on the TSC version. This is the same thing with the 375 on Southeastern Highspeed, I do hope this gets implemented as it is a realistic part to the 377. Also to add to the inaccuracy of the 377, some of the trains have numbering starting with 1 on the other 4 digit number code for the train. The 377/1 has different Headlights compared to the /4 which is on the route. I would love DTG to replace the ones that have these numberings and put in the realistic version of the train as it would make the route better as well as add more realism to the route.
1) Only the 377/2, 377/5 and 377/7 have pantographs. The 377/4 is single-voltage 2) DTG are aware of the 377/1 issue. The problem simply put is that there aren't enough 4-series numbers to fill out the timetable, but they weren't going to do a third variant of the platform.
There are different versions of the train represented in game. Not all 377s and 375s have pantographs, the vast majority of them are DC only. 375/9 (which is represented in game) is DC only. 377/4 is also DC only and some 377/1s have the same headlight design as /4. Only Class 377/2 /5 and /7 and Class 375/6 are dual voltage.
The only inaccuracy with the 377s is that on BML, the /2s do the Milton Keynes services, not the /1s or /4s due to no third rail up that way. The /1s and /4s are also very similar in appearance minus a few cosmetic details.
The class 377/101 - 377/139 have smaller headlight clusters while 377/140 - 377/164 have the ones we are more familiar with
