Hey! I know I'm late but I have a 1988 Yamaha DT125R swiss edition, which has the 3DD code. I checked the parts diagram and the 3DD-14610 pipe is originally the 1988 swiss edition pipe, which is supposed to be heavily restricted. I'm pretty sure mine only has a catalytic converter, I was hesitating about cutting it open but now that I saw your pictures I think there's no reason to do so. Your pictures look like the pipe really only has a catalytic converter. But I must ask, were there any restriction cones or washers that you didn't take a picture of?
Thanks!
