I my self wouldn't worry too much about the patches, they're easy to replace if you find they leak... I'd look into the cracks though, even though I imagine they're from folding the boat for long periods and are just in the urethane coating, not all the way through the PVC.
If I were looking I'd be excited about that boat, it's not an epic deal but far from bad if it is indeed in good condition...
Yesterday's gone on down the river and you can't get it back. - Agustus McCrae