Yes, it is.
I got a set of caps from Partsconnexion, 10µF 10% Mundorfs and well they may have been quality but they were not within 10%. Ranged from 11.9-12.2. Contacted PC and they needed this $5 parts order returned for replacement. Shipping outside the US starts at 25 for a package so that wasn't going to happen.
Contacted Mundorf and they eventually offered to replace them with a shipment from Germany. Excellent...until I measured the caps. These were 11.7-12.1µF. No before you jump all over my calibration of the meter, I check a number of caps and have some that were professionally measured and marked and the ones that were rated 6 measured 6.12 and I would get 6.07 for some such close enough for mil-spec.
May make good stuff but damn they sure are insistent that want they made is right. I get that from a few of the € countries.