3.8 metres = 12' 6", which I think would make it either an S300 or an S400.
The main (visible) difference between them is the S300 has a removeable bow dodger whilst the S400's is integral.
There are details visible in this (finished) ebay auction, Item number: 320013698982:
The S400 is slightly heavier than the S300, and can take a 45HP rather than a 30HP outboard.
I'm not sure what the number refers to - It's not length as my S250 is 3.2 metres long. I think it may be to do with maximum outboard power, as S250 = 25HP, S300 = 30HP, S650 = 65HP. Doesn't work for the S400 though