I just bought two slightly tattered 52" Super Surfers. I imagine they are a few years old. How can I tell how old they are and where can I find a manual for them since they are older? I would like to know the number of spacers in the casters for the size of the cut and stuff like that. Also any info you guys could give me about these would be great (never owned a stander). How often do you cahnge hydro oil and what kind of oil do you use? Thanks for any help.