Tung-Sol 322NF3 is this 6SL7 or 6SN7 ?

And if it is 6SL7 can I use it in place of 6SN7 in my Audio Electronic Supply (Cary made) AE-3 preamp?
322 is the EIA code for tungsol, so yes it's a tungsol tube. That code says nothing about the type - that should be marked on base or glass. 6SN7 and 6SL7 are not swappable unless the component is specially set up for it (some are. Cary among them... not sure on AES though) 6SL7 has more gain (higher mu) so it will be louder (more distortion perhaps) if it works at all.