Here's my attempt at reassurance (but, as you know, nothing is guaranteed or set in stone ... this is just my opinion/thoughts).
Apple just released iOS 5.1.1 and there has been no rumbling about another upgrade. As far as we know, there is nothing in the pipeline; iOS 5.1.1 is the most current for the foreseeable future.
The iPad that is not jail breakable at this time is the new iPad2 that was released AFTER the iPad3 was released (the ones sold since March 16th). It has a slightly different chip and so it's different. However, as you are getting a refurb, your odds are pretty good that you are going to get an older iPad2 versus one of the newer iPad2s that were produced after March 16. I'd say that it's a pretty good bet that it's one of the older ones (as more people will return old iPad2s versus new ones).
Again, all of this is just a guess, but you should be all right. Of course, you'll know for sure when you get it. Good luck.
Marilyn