I wouldn't spent too much energy trying to figure out what happened to the OEM tires. You'll never know for sure how they were treated by the PO.
However, if you keep those COMMANDER II's at about 40 psi, you should be very pleased with the outcome. My current set of COMMANDER II's have 16,877 miles on them and I expect to get another 2,000 more from the rear tire and perhaps 7,000 or 8,000 more from the front tire.
Unlike too many products, these tires have greatly exceeded my expectations and live up to the advertisement hype. Michelin deserves much praise.
Montani Semper Liberi
2003 Vulcan® 800 Classic - Pearl Mystic Black
National Cycle Custom Heavy-Duty Windshield
Mustang Two-Piece Wide Vintage Touring Saddle
Volar SissyBar/Backrest - K&N Air Filter
Viking Quarter Circle SaddleBags & SissyBar Bag
Scootworks Sprockets (18/40 - 2.222:1 ratio)
Baron 3" Bullet Tachometer - Engine Guard (black gloss finish)
Michelin COMMANDER II front 130/90-16 73H, rear 140/90-16 77H
EK X-Ring Chain, Deer Warning Whistles & BackOFF® Brake Module