It all comes down to infared frequencies, if it's the right frequency yes, if not, it might turn on your TV or open your garage door. which might be cool too. lol
Hmm..when the old Chip not combine Sound and InfraRed in one IC it should go, for a exact Answer i must see this Chip.
A another Way: You buy one of this little Sound-Record Chips there already build together, record the Sound of the old Chip and combine it with the new Chip, that is a few Steps easyer than the first one.
Over the years Most lasertag toys have been able to play with others. If they have a code you can punch in. The guns that came out about 4 years ago with the glasses that had targetting huds in them, were compatible with 10 other systems through the use of going in and changing frequencies. I'd somehow figure out what the frequencies are, and then change some of those up.