Paul,
First, do I need to do the upgrades?
That's up to you.
If you're already on DCS 4.10, upgrading to 4.2 won't add any new O gauge features. Otherwise, I'd suggest upgrading.
Secondly, I don't remember when I bought my DCS system. How do I find out what version I have?
To learn the software in your DCS Remote, just turn it on and watch the screen for the version number.
To learn the version number of the TIU, power on the TIU and the remote and press:
Menu/System/TIU Setup/TIU Version
To learn the TIU's hardware model number, turn it over and look for a sticker or heat stamp on ht center of the bottom with the TIU's REV number. If there's no REV number, it's an original Rev. G.
Do I need to upgrade for a PS3 engine?
No.
This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site! Click on the link below to go to MTH's web page for the book!