Your support usually comes from the module version, not the client version. You need a minimum version of NLSQL 5.1, but there is footnote on this version that states you need a minimum client version of 7.4 SP2 or later so the answer should be yes. There is a footnote saying you need to also install a quickfix with NMSQL 5.1 as detailed in esg97370 - this seems to apply for NMSQL5.2 too. The escalation is not accessible in Powerlink so you will need to log a call to get the patch.

Actually, what it says there is that you need 7.4SP2 and module SP1 with at least build 281.

They give following link ftp://ftp.legato.com/pub/NetWorker/Updates/NMSQL/NMSQL511_build281

... but I have no idea if that works as at my current desk ftp is banned.