Welcome to the forum TxRick! Yup I've never seen any pontoon boat without those welded eyes either. Suggestions..... Use at least a 2 inch strap to ratchet your rear end down. Or shorten that orange strap on the right. Those knots would pull out if you really needed that strap to hold your boat. JMO.
My lug is attached to the back decking as shown and I actually had a bracket fabricated up and bolted to the trailer frame to attach the other end to keep the strap so the strap wouldn't be resting on depth finder bracket. Works great!