Lexan or Other ??

Good morning this is my first post to the forums, my brother and I have just purchased a 1984 Hobie 16, and are in the third week of a six-week project to restore her.
We have Hobie's back in the 70s, and now are getting back into this wonderful sport! We removed the existing rudders to refurbish them, there are codes stamped on the top of the Rudders that were under the casting (XXT AH "M") will this tell me if they are Lexan or other?? Reason being... either want to sand them or paint them or none of the above, need to know what the material is, so as to know how to finish them, as always thank you for your input !!

The codes mean nothing - they were probably mold or some other production identifiers back in the day.

A 1984 boat came with Lexan rudders. They are white (or a light yellow from UV exposure), have a slight texture to the surface finish, completely solid (heavy) and very flexible when compared to other rudders. Paint will not stick to them well due to the waxy surface. You can try sanding these smooth, but it is laborious. Lexan is very tough.

If the rudders are as above (white/faded yellow), but have a shiny, hard surface finish, then they are ABS - really not suitable for a Hobie 16 (they were the original rudders on the 14). They inevitably break off just below the rudder casting.

Newer plastic rudders were made from Nylon.

Thank you! I have sanded off the yellow tinge, they now look acceptable...Glad I read your post, was thinking about rattlecan 'em ..but not any more!
They will go back on sanded as is.