Randoku does not do that at the moment - I could potentially extend my parser to keep a copy of the closest archived snapshot url from the archive.org public API. I will explore this - thanks
At its' current state Randoku mirrors Pinboard's features to a certain extent, but I'd like it to be much more than an archiving solution.
I'm working on introducing "read it later" features (à la Pocket/Instapaper), annotations, discovery of relevant content via RSS and re-discovery of content already bookmarked (which is what I liked about Link Drop).