I agree that if it's unlisted or an unknown, you should go with the default clearances. BTY, the original Buck stoves did not come with glass...
Model 26000, 27000, 28000 & Carolina 1 @ 11 Here's a link to some parts and a manual for the older Buck Stoves. Clearances for the freestanding...
This is a very old Buck. Looks like my brothers old stove that is about 15 years older than mine. He bought one of the 1st ones of the model...
N8WGB here. Not real active any more....