Weird fork stanchions

I have a set of Commando forks with a single disc - I think the sliders are Norvil. The bike has been standing for 18 years, so I am renovating it. I noticed the fork stanchions are pitted so was thinking I'd need to replace them. Then I found a pair of new stanchions at an autojumble for less than a third the price I'd have to pay for new ones normally. I have dismantled the forks and the first thing I noticed is that the current pitted stanchions have the oil "oil-bleed-holes" much higher up the tubes than the replacement stanchions. I checked all the diagrams on the Andover Norton site, and the replacement ones seem to be correct. I can't find any models with bleed holes higher up. I am wondering if this is a Norvil modification?

The second thing I noticed is that the replacement tubes are 2mm longer and the taper for the fork yoke seems to have been home-machined on the pitted current ones. Does anyone recognise these fork mods? I am wondering if the standard tubes wilI work okay in the Norvil sliders? I will enclose pictures...


https://flic.kr/p/WGKQ3u
https://flic.kr/p/Xnv1tm