yes
No in a sense the word uncommon would mean more rare in most contexts, nonstandard, you could say, unconventional, unorthodox, irregular, etc.
The boy was a nonstandard student.
Independent Service Organisation(ISO)
we were using the nonstandard set of measurements
Iso- means same.psp
'ISO' in a personal / dating ad stands for 'In Search Of.'
ISO means "In search of" - for example, someone might post ISO gently used stroller.
standard or imperial measurements are in : inches, feet, yards, pounds, gallons and asuming by nonstandard you mean metric measurements, they are in, millimeters, meters, kilometers, kilograms, liters. .........TADA!
"In Search Of"
similar
ISO means In search of. For example, a Craigslist post could say ISO a gently used queen mattress.