Here's another example -
https://www.inlinetube.com/products/ctc6703
I have a line with this part number on it. It will not fit the 1968 with 250 and 1MV. It appears it will fit the 1BV.
The good news, if you ordered this from Inline Tube and you get it and it doesn't work, You can email them and tell them that it doesn't work and you want to send in your existing tube to get duplicated instead they will duplicate your old line.
Or, you can just send them your old line for duplication. I'm not sure how you initiate that, but you could email them and ask.