Questions about Ford 4.0L SOHC chirping noise.

Hi Scotty, I need to purchase a vehicle for my new job coming up this summer. I've eyed up a 2004 Ranger with Ford's DUMB 4.0L SOHC engine. When I went to check out the vehicle it was fantastic. The seller's grandpa owned it his entire life and took it back to the dealership every 5000 km for a service. When I went for a test drive everything seemed fantastic about the vehicle except for one small noise that's got me concerned. When running there is the tiniest of chirping noises coming from somewhere in the front of the engine (kinda like a really quiet squeeky shopping cart wheel). I didn't have time to check the pulleys at the time and the seller told me his mechanic (whom he spoke to over the phone and just described the noise) had guessed he might just need to grease up "the timing belt". Well, this engine 1. has timing chains and 2. from what i've read is prone timing chain issues. I've looked into the issue online and it sounds just like the camshaft synchronizer issue lots of people have had with ford motors, an easy fix I'd do myself. With this model though, the 4.0L SOHC, I dont think there is a cam synchronizer! I'm totally lost and don't want to back out of the purchase because this vehicle is otherwise perfect. If it is as simply as a pulley bearing running out of life, i'm not worried. I am worried about accidentally buying a lemon. Do you have any advice on what I should check for next time I see the truck?