If you link the place you bought from, people with experience with them can better tell you if they might be good or not.
If the cells are all actually new, (not merely NOS or new old stock), and are still in their original boxes as batches and are all the same batch, they are probably already well-matched.
If any of those are not true, then it might be safer to at least do basic internal resistance testing, to be sure that all the cell groups end up with about the same Ri and so they operate about the same under load and charge.
Testing for capacity is a second test you can also do, to ensure each group is about equal capacity, but the Ri is more important for equal voltage drop or rise during current flow. As long as the Ri is ok and equal among groups, then whatever BMS you use should take care of monitoring when cell groups are empty or full, and the lowest-capacity group will determine how much capacity the total pack has and how long you can ride.
There's a few people here on ES, like Pajda,
memberlist.php?mode=viewprofile&u=47285
that do a lot of cell testing with various equipment, and those threads would be the best ones to use as a guide for good testing equipment (and how to use it). Most of the threads are here in this subsection of ES.
If the conditions noted previously *are* true, then you can probably just do some random voltage testing of a few cells in each box to ensure they're already voltage-matched to each other, so you aren't connecting ones in parallel with wildly differnet voltages.
If they are actually new and same batch, etc., they should be virtually identical voltages to the hundredth of a volt or so.
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