I'd ride it this weekend; If you must, go by the shop, and talk to them.
Tell them that you think the bike is worth more than you paid for it.
See if they made a mistake, and sold you the wrong bike, or gave you a great deal. If you are someone that brings them business, maybe the owner did it on purpose. Sometimes Karma rewards instead of punishes...
See where it goes. You have done nothing wrong; best case, they can ask
to buy it back for what you paid. A judge would laugh at this, if they tried to make trouble.
You paid for a bike; I'd ride it. As long as you didn't swap the price tags, it's not your problem; if the invoice has the model number and serial number of what you actually bought, it's yours, Legally.
I'd rather have the better bike; parts drilled for weight are not more likely to break, as long as the guy drilling them knows where; it's just more labor, thus more expensive. Every large bolt or plate on my dirt bike is either drilled, magnesium, or titanium...it's broke me a lot more that I've broke it...
Red '96 Cougar XR-7 240k mi. '02 4R70W, PST DS : '03 PI engine, 04 maf, 24lb injectors, 2.5" exhaust, '02 4r70w + Jmod, DirtyD0g TC + cooler + 3/8" lines, 255 walbro fp. Alpine system.
Black '96 Cougar XR-7 (Lazarus) 210k mi PI Intake, '02 4R70W, Jmod, PST DS, GrogTune, Konis, Mark LCA+Poly, racecougar Custom Engine Chain, and JL and racecougar Bracing.
Black '97 Tbird Limited Edition, '02 4R70W, 255 walbro, PST DS, PBR Brakes&SS lines, Toicko Blues & Springs, GrogTune.
"War Is Peace. Freedom Is Slavery. Ignorance Is Strength." - George Orwell.
Truth Isn't Truth. - Rudy Giuliani, 2018 Award winner, “Most Outrageous Diversion” by MSNBC for this quote