I've got a dozen MK1s purchased over the last 18 months or so, but don't have your problem. Mine are coupled in two sets using the Bachmann close-coupling supplied with them. My only problem is using Kadees on the outer ends of the sets as the NEM pockets are a tad too high.
Bachmann do sell replacement bogies at around £2.50 a pair if you want to save a bit of time.
Bachmann do sell replacement bogies at around £2.50 a pair if you want to save a bit of time.