But as it's rated for 400VDC, it's probably OK on 120VAC.
Don't forget the saying
"Assumption is the mother of all fuckups."
If these caps will be connected across AC lines, make sure they are "Safety Certified Capacitors" and AC rated.
They're usually classified as either X or Y capacitors.
X for use in line-to-line applications and type Y for line to ground applications.
Capacitors designed for use across AC lines are special in that when they fail, they fail as "open" and not as "short circuits."
So you can imagine what will happen if a capacitor used in an AC line-to-line application failed as a "short." -- KA BOOM!
The caps also need to be able to withstand multiple high voltage impulses and operate under normal AC voltage conditions.
i.e. for example 250VAC (rated voltage), 1500VAC (withstanding voltage), 2500V impulse voltage
Actually Historically speaking they are polarized... a polyester film capacitor is two long parallel plates (ribbons but the idea is the same) and the polarity came from old tube days and to a point even today for capacitors of similar construction. The major exception being metalized layered monolythic caps.
The standard american symbol looks like this: This end was considered the inside foil and therefore more susceptible to noise pickup > -----|(----- < and this end was commonly accepted as the 'ground' end or outside foil. "From the 1949 Radio Amateur Radio Handbook" Published by the ARRL.