My 72 bob is designed for 27" x 126mm, and I run 27" 126mm 6spd, but have tried a 700c 130mm 8spd in there and it did fit, but it was fag paper tight between bottom cog and the chainstay.
So being safe I would say an 8spd 130mm hub running only 7spd with a spacer in the wrong place would defo be OK.
My 72 bob is designed for 27" x 126mm, and I run 27" 126mm 6spd, but have tried a 700c 130mm 8spd in there and it did fit, but it was fag paper tight between bottom cog and the chainstay.
So being safe I would say an 8spd 130mm hub running only 7spd with a spacer in the wrong place would defo be OK.