There's a lot of definition for short stroke absorber. There;s one, which is the shaft(silver shinny thingy) and it's barrel (body) was short. and another is the shaft is short but the barrel is still long.
Did you saw a welding line around the original welding line on the absorber? If not, they cut the tip of the absorber short only. Nothing other is done to your absorber.
RM1200 is definitely OVER charge~! For you setup, i think you can get it around RM350 in our shop (w/o the spring).
Lastly, my recommendation, you can try use, original spring, cut one round off, heat-treatment at the point of the last quarter of the cut edge to make it's angle less steep so it will sit better on your absorber's bow. then cut one inch off your stop bump~ and walla, you get a two finger gap between your wheels and mud-guard and a comfort ride.