Should be easy enough to change, there's probably a 5mm spacer each side which was put in there by whoever changed them from 120 to 130 in the first place.
Goldtec? If so, you should be able to buy the axle and end caps for 120mm - unfortunately, you do need both, as both parts are different for each OLN dimension. You also have to take the bearings out to replace the axle, which probably means new bearings too.
Should be easy enough to change, there's probably a 5mm spacer each side which was put in there by whoever changed them from 120 to 130 in the first place.