The UML290 should work fine with your cradlepoint as is. As another member pointed out, however, there are different form factors for the sim cards. The 4620 uses the 3ff smaller micro sim while the UML290 uses the 2ff standard sim card. My recommendation is to purchase an adapter off amazon and use that with the UML290 but if you don't, you won't be able to use the sim card with the UML290.
If you want to be mad at someone - blame apple. They demanded the 3ff with the iphone 4 so you were forced to get a different sim card. They claim it's to get more space in the phone but when you compare the cradle sizes of both, they didn't really save that much space but that's my .02
They're also the ones leading the way to an even smaller sim card format in the iphone 5
If you have problems with the LTE modem and MBR1000 setup try using a good quality USB extension cable to place the LTE modem in a different location to receive a cleaner signal. After working for two weeks with a Cradlepoint tech that ended up fixing my problem.