Follow up. MWS states the rims are tubeless since about 1985. To confirm this, you may see the sealant tape such as Rich V6 or two different version I found in mine once the tires were removed. Several motorcycle and lowrider websites are showing the use 3m 100% silicone as an "after market" sealant. There is also a 3m sealant tape made for difficult surfaces.

So... if you see a sealant... tubeless!!

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