Seein' as how you haven't received any kind of response yet Michael, I'll tell you my thoughts here:
I don't really have any personal experience with those particular retro-style Girling shocks, however while I believe there would be no problem fitting them on your bike(with of course the properly sized sleeves fitted inside the shock's mounting holes), AND while think they're really cool lookin', I doubt that they'd be any kind of an upgrade for you, performance-wise. Ya see, I have a feeling that the rebound damping on those, or the lack of which anyway, would pretty much be on a par with the inferior stock shocks which come on our bikes.
I feel this way because I have yet to have found, or have heard of, any shocks on the market at such a low price as those and which turn out to be any sort of a performance upgrade at all.
(...hope this helps)