All my bikes are 130mm. All my wheels that use 7-sp freewheels were modified to fit into 130 by installing longer axles and extra spacers on the LEFT, non-drive side, just as GrayJay says, then recentering the rim over the new axle. This makes for a more durable (because more nearly symmetrical) wheel. It does not break axles because the distance from the right-side hub bearings to the locknut is the same (obviously) as on a 7-speed 126mm wheel. What broke axles on 130mm freewheel wheels was the attempt to use the extra space to mount 8-speed freewheels -- this did move the right-side bearings farther to the left, (and we can't have anything moving left in an election year now, can we?)

The key to doing this is to set up the axle so that the outer face of the smallest cog rests 3.5 mm from the outer face of the right locknut. This should give 1 mm of clearance between chain and seatstay, just enough so that the outer plate of the chain will not catch on the stay as it rotates outward during the shift from smallest cog to next bigger. This allows you to reduce the wheel asymmetry as much as possible and is well worth doing accurately.

A 130 mm 7-speed wheel shows that the builder worked hard to optimize wheel design.

Ah, missed that FW in the meat of the OP.
Well, there were 8 speed freewheels released as a challenge to the freehub. So, it goes to presume 130mm hubs were made available. The idea failed miserably quick...thankfully.

Fixed it for ya! ;)