P1870?

I saw this referenced in another post. Seems it is a common problem in GM transmissions. One of the posts I found quoted a TSB that gave a build date in 1999 where the valve body was revised. My S-10 us a 2000 and it sometimes shifts rough from 1st to second, I thought it was just due to the under powered 2.2 as my old 2.5 manual I had to wind out pretty far is first before hitting second anyway. Can I tell if my transmission had the new valve body or the old style? I think I saw somewhere (door sticker maybe) my truck was build in nov 1999 so I'm real close to the change time. If mine is the old style can I fix it easily myself? Can I carry a spare and swap in if it breaks sometime on the road ( I drive a lot and can't afford downtime so I do all my own work and carry a full size spare, spare fluids and filters, spare fan belt, spark plugs and wires, spare lights and fuses as well as a toolkit). Thanks Eugene