Difference between a 608zz and 608 bearing?

I have started the swap to go to this extruder on my 3D printer. As such, I am taking the time to go ahead and use new bearings. I have a set of eight that came from a [one week old] skateboard someone broke, but they are 608zz. The BOM of the extruder calls for 608.

From what I can see, the only difference is that the 608zz have a plate that covers the ball bearings, versus 608 which appear to be open. Is this true? and if not, what is the difference? Can I use the two interchangeable?

thanks in advance! 

Yes, the letters after the numbers designate whether it has shields( metal plates) in plastic or metal, as well as the precision specification. The same looking bearing can cost anywhere from $10 to $300 or more depending on the precision.