It will be useful if you have preview version of SDK or something wrong run in last SDK (for example in 3.2.4 there is problem with timer, so I have to test in 3.2.3 or by mistake I built version based on 4.0 preview).
maybe be useful to write in red if current SDK ver < max (not preview)
Just to make sure I understand, you're looking for some kind of indication in the Export Wizard of the current SDK as a last minute check before exporting an app, correct?
Just as an FYI, the 4.0-preview build (and any beta builds that we release) do not allow app export, so you shouldn't have a problem accidentally building with it. 
I'd like to see the same what is in preferences
sdk 3.2.4 has bugs i timer menu so I have to use 3.2.3 to test, and don't remember to change it before building store version
I've built a lot of version because sdk errors on devices so it would be useful to remind dev to change sdk
