I have one of those rims available for sale but it may not be as perfect as you want. It is from a TY250C and has been used for trials so has some minor damage. I have not seen inside it as it still has an old tyre fitted.
In case it is useful info, the TY250C and TY250D had this style of front rim as standard.
If you are interested, let me know and I'll pull the tyre off and take some photos.
David