From what I read about it
From what I read about it they used parts from the original masters and then they got Roger to do the vocoded vocals as part of the deal. I think he even did the arrangements for the vocoded stuff. At least at the credits he's listed for both performance and production
That shows how the 'big boys' (like Dre) do their stuff sometimes. If Dre needs a bassline to sound like a Bootsy bassline he'll try to get Bootsy down the studio to play the part. That's how he gets a lot of his authentic sounding stuff.
From what I read about it they used parts from the original masters and then they got Roger to do the vocoded vocals as part of the deal. I think he even did the arrangements for the vocoded stuff. At least at the credits he's listed for both performance and production
That shows how the 'big boys' (like Dre) do their stuff sometimes. If Dre needs a bassline to sound like a Bootsy bassline he'll try to get Bootsy down the studio to play the part. That's how he gets a lot of his authentic sounding stuff.