I personally would not pay 35bucks for a washer.
I dont remember there being one on my pan plug but if i was in your situation i would have called Tator'sGarage and asked him what material it is and picked one up at the hardware or autoparts store. (at the same time i would have ordered a few Mopar Oil Filters from him

)
TQ them to 95 INCH lbs, going in somewhat of a "crossing" pattern. Don't just torque them one after the next, get them all snug tight then zig zag back and forth across the pan keeping track of which bolts you've tightened already then give them all a final check at the 95 in lb setting.
Yea, finger tight first then the correct way to torqure any long gasket is from the
CENTER out:
Examples:
You must be registered for see images
You must be registered for see images
The goal is to have the gasket spread out from the center out.
If you start from the ends and work your way in then the gasket could end up slightly buckling. -BAD
If you start from one end and work to the other the final few bolts/gasket may not line up perfectly. -BAD