Lengths of straight sections:-
397 = 290 mm = 397-14753-00
1E8 = 320 mm = 1E8-14753-00

Baffles are identical except 30 mm longer plus 10 extra holes
The shorter baffle you have is the correct one for an 1E8.

Will mismatch baffles be a problem. Well tuning relies upon back pressure. So yes you need two the same. They don't have to be identical to originals so 397, 2R7 or even CS5 will probably do as long as a pair!
On eBay at mo there is a Yambit pattern for sale. They don't do them now

and you need a pair!
https://www.ebay.co.uk/itm/325172496519?hash=item4bb5ca8887:g:UfUAAOSw2slib6bZInterestingly the 397 & 1E8 exhausts are externally, including mounts points identical. The position of the first baffle plate internally is also same. Only way to know if any differences you would have to carve them up. Are they different, doubt it

Cheers
-Mike
PS Give that oily pair

you have a run over with blowtorch and wire brush. Lot easier to handle

Oh throw away the JIS screws that hold the baffles in and use M5 x 10 long cap heads. Lot easier to use Alan key than trying to balance silly screws on driver
