Negatives harmful to one another while archiving?

Can negatives be damaged by long term contact with eachother? Here's my problem:

After developing and making contacts of rolls of 35mmTri-X, A&I labs here in SoCal returns processed B&W negs in a small acid-free envelope with the negatives cut up and placed on top of each other inside the envelope.

Other labs I've used have actually placed the negs inside archival sheets before contacting them and then returning them in the sheets themselves.

If possible, I'd like to leave them untouched until I need them, so can I leave them the way A&I delivered them without worrying about long term archival?

Thanks!

I do it that way and it doesn't seem to cause problems.

I like my contact sheets made with the negative in contact with the paper, so I can judge sharpness from the contact sheet.

And just be sure they are stored in a cool, dry place. Humidity will make them stick together.

if they are already cut, why not slip the strips into a neg storage sheet, they can then be stored flat and no issues of sticking to each other

I'd buy archival sleeves to replace the envelopes. The lab may return them to you this way, but that doesn't mean you must leave them in the envelopes. Switch them out of the envelope when you get home from the lab.

recently detected some negatives from the 60's, which where stored rolled up in little plastic containers. It seems like that didn't do them any harm. But they never had direct emulsion to emulsion contact... which could happen with your strips. (maybe this also would not do anything to them...)