I have imported into my Sonar X1 some old recordings made when guitar tuners were not readily available so our guitars were not in concert pitch. Consequently I am unable to add some sync sounds, in concert pitch, to the old recording. Is there any easy way to identify the pitch of the audio and then change it to concert pitch? 

There is a program called Melodyne DNA, which i own, that would work great for this. But it may not be easy and may invlove allot of intensive work or it may not.
 
Cj

If this is just one or two guitars, or if the instruments are on separate tracks, Melodyne (polyphonic) would help and you could raise it all to concert pitch.
 
If several instruments are mixed, I would take a tone (like one output from a tuner) and vary it until it sounded in tune and then read the frequency.  With that information, you could either (a) tranpose the whole track or (b) tune your new instruments to the target frequency.  I think (b) would sound better.
 
Someone may know of a tool that does the analysis you are requesting automatically but I do not.
 
Just as a historical note: I used to put a tone or piano note at the first of a two-inch (24-track) master tape in case we ever had to tune to it later, or use varispeed to get it in tune with a piano or organ.  Ask me if I miss those days...what a pain

Why not detune your synths to agree with what the guitars are tuned to?

+1 on the detuning the synths. Every half decent synth has a fine tuning knob. 

PS Alan if you ever bump into Buzzcocks please tell him we miss his videos!

To clarify, I’m a relative beginner with Sonar and still struggling to get the basics.  The audio track I have imported is mixed instruments (6 string and 12 string guitars and 2 vocalists). CJ and Konrad, I think the Melodyne DNA is streets beyond me, but sounds really useful for serious musicians.  The answer for me is detuning the synth which I knew nothing about previous to this query so thanks Bristol Jonesy and Sharkey. Regarding your PS Sharkey, who is Buzzcocks and his videos? The only Buzzcocks I know of is the Punk Band, still performing I believe. 

Hey, Alan.  You are wise to go the synth tuning route and you may try to get a tone that sounds right, put it in a tuner and see what freq best matches the track so you don't have to start over trying to get each synth in tune.  For example, if a tone at A=454 HZ is pretty close, then you can use your tuner to tune all other instruments to that standard.  Otherwise, you will have to start from scratch trying to get each instrument you record to sound right. Hope that makes sense.

Alan in Cram
Regarding your PS Sharkey, who is Buzzcocks and his videos? The only Buzzcocks I know of is the Punk Band, still performing I believe. 

Ha sorry about that Alan, I guess I thought Buzzcocks was a bigger star than he really was. He was a cult chav character on YouTube and as funny as hell. All set in Cramlington. And then one day all of his videos disappeared without trace, the man behind them having taken them all down. They're still uploaded in various places though. 

I've now googled and see what you mean. I'll ask around locally.