"The agent I am going with seems to think that elaborate sim prep is required to pass even as a non type rated FO."
The simple answer is no. Many guys in the past have passed the sim without the sim prep. B767 is still an airplane and flies like one. Gtseraf has a point though; if you've been flying only full glass cockpit, it MIGHT be helpful. But airplane's an airplane. Just familiar yourself with the profile/callouts and the general pitch and power settings and you should do fine. Longreach started this sim prep thing for guys with a lot of cruise time, but no real stick time - and was caught on by others. Either way, we're still getting pilots who you wonder if they're Frank Abagnale wannabes...