Believe that's a 74, maybe a 73, but IIRC that color was 74. I had a 75, orange bike in Aggieland, go figure.
The main thing about 2 strokes that sit a long time is the crank seals can dry rot. They're pretty high quality in the RDs, but you never know. A pressure leak down test of the crankcase can tell ya and you can soap the crank seals to check for bubbles. A good seal is necessary. Too much leakage and it can be cranky and may seize if pushed. Trust me, I know these motorcycles, I've owned over a dozen Yamaha 2 stroke twins over the years, most have been raced in CRRC (which became CMRA). A few of those were water cooled TZ250s. They suffer no fools for tuning.
I once had 4 tickets in a year in the BCS area on my 75 RD for speeding and "exhibition of acceleration" or "unsafe start from a stopped position".
I chilled when the judge told me ONE MORE BOY....