Very basic Windows update question

[TwistedHelixis]

I manually update our primary school server (2012r2) with its monthly updates (no wsus)

 

If I find an old .net update in the optional updates list am I ok to install that update even if I have installed other .net updates that were in the important updates list, or will it go over parts of the .net software with older code?

 

I have always assumed that if Windows update lists an update then its OK to install, even if it's not in the date order they were supplied to the server but just wanted to check.