That is the hardest thing to say for certain and I see the questions in various forums: What guitar was used on (fill in the song title here).
And the fact is, unless Edge says in an interview, it's hard to know for 100% certain. Plus, as mentioned, there is usually more than one guitar on a song.
Another argument I hear is, "well it was used in the video". That means little to nothing.
What is used in the video does not mean it was used on the song. The "Walk On" video shows Edge playing the 1994 (made in Japan) Arctic White finish Telecaster. I'd never seen him use that for "Walk On" live. And the guitar was tuned to C# or D for "Sunday Bloody Sunday"; hence the guitar being set-up for intonation in a far different tuning than that of "Walk On". And, there's no interview footage of Edge saying it was used for "Walk On". So there is little to show me that was used on the studio recording.
Walk On (video)
http://www.youtube.com/watch?v=gwKEdFoUB0o
Another example is Pride. "Edge is seen in the "Making of the Unforgettable Fire" documentary playing his Les Paul Custom". Yep. Is that on the final mix? Uncertain. It's possible but like the "It Might Get Loud" documentary, it's footage of the process but not something that definitively shows it made the mix.
Pride (In The Name Of Love) - You can see Edge playing his Les Paul Custom at about 1:30-ish into the video
http://www.youtube.com/watch?v=ZmPtKsSZkmE&feature=related
I remember speculation about "Beautiful Day". Some insisting that the alternate video showing the band "in the Studio" proved that a Les Paul was used. What it proves is that Edge had one there the day that video was shot. It proved he may have even played "Always" white later became "Beautiful Day" on a Les Paul (Goldtop).
Beautiful Day (Eze Version)
http://www.youtube.com/watch?v=OFYtJHSI0fY&feature=fvst
And the there the It Might Get Loud documentary that shows Edge playing "Get On Your Boots" on a Country Gent and his SG at another point.
Edge - It Might Get Loud - "Get On Your Boots" (at 1:04)
http://www.youtube.com/watch?v=2LPQABI3xHA
We can speculate, based on the sound of the guitars and such. Don't get me wrong, there is nothing wrong with trying to figure it out. And that is a fun thing to do; to try to figure out what is what and how the heck did he get 'that' sound.
So... long answer for a short question... but... LOL... Do I think that tobacco Tele was on "Unknown Caller"? I am not so sure. I do think that it may be on "Magnificent" and there was some studio video to suggest that it was at least tried, at some point.