Need help id she-ra production number

Hello guys, Well this is my first time posting here. WEll bought this she-ra cel and on the glimmer layer it has on the bottom of the cel ppstk 502 I'm sure these are seq number but not sure what stk means is anyone know please post.
Thank you in advance.
Starfighter

http://moondreams.rubberslug.com/gallery/inv_info.asp?ItemID=65272