Wayne,
I don't have a 125 parts manual, but the 160 parts manual doesn't list the connecting rod separately from the crankshaft, just the entire assembly.
I have a 125 price book, it shows a part # 0251.47.270 for a Biella, which I think is the connecting rod, no listing for your part number.
At one time it was a common practice to straighten a bent or twisted rod- I've seen mechanics clamp the big end of the rod in a vice, insert a rod through the wrist pin bushing, and twist the rod back into shape- an arbor press may be enough to push out a lengthwise bend.
If the big end bore and the small end bore were slightly out from being in the same plane, the piston would still go up and down the cylinder- I guess you'd need to worry about valve pockets on the piston crown if it was badly twisted. Even a small bend along the length shouldn't be more than the wrist pin couldn't compensate for. I'd want to know what caused a rod to twist before putting it back together. You could do a dye penetrant test if you're worried about stress fractures after cranking on it.
Rick
125 price list.jpg
Edit: Found a Youtube video- it looks crude, but might work for you.
https://www.youtube.com/watch?v=EisGc4IuYMg
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