r7 just tells you it's a 8.8" 4.10 LS axle...no spine counts. You gotta take a tape measure to the axle housing to confirm.
Yeah they are VERY hard to come by. How many L2's do you see driving around? Add that to how many have wrecked. yeahhhh. lol.
You can tell visually too....take a look towards the right of the picture where the brake flange is on the housing....
31spline (note the 'dip down' because both wheel bearings are the same size)