Exhausts/conical mount
 

I've come across a seller nearby who has an exhaust system part no "EA EXH/MUFF 320/360". The current Vans catalogue shows a "-1" at the end of the part no, does this mean a significant change of design, or is it the same p/no that's always been used and the seller has just omitted the "-1"?
I am using a conical mount 0320, any comments on whether that would be a problem with this system? The catalogue wording does not mention mount type under this system, however the 3 and 4 systems do differentiate between conical and dynafocal.
Thanks from the south pacific!