The correction tables are generally for the meter when used as a microphone through the line output. That is, when you take the output from the RS SPL meter into your sound card (or whatever), not when you are looking at the meter itself for readings. The line out is flatter (no weighting).
While there may be differences betwqeen new and old meters, I strongly suspect the variation in most of the published tables is sample-to-sample, not analog vs. digital. As Ethan said, it is not a terribly accurate device. You can spend $200+ and get a more accurate SPL meter*, but it is probably not worth it since with the RS meter into your sound card and correction table many inexpensive software program (e..g REW) will measure your system far more easily than you can. If you just want to use it to match levels, then use the RS SPL meter above about 40 Hz and below 10 kHz or so and you should be fine.
HTH - Don
* A good calibrated meter that has flat response may run $500 to $2000+; a decent measurement mic ~$500 - $1000 (plus preamp and software); and an Audio Precision or Agilent audio test set $25k - $30k. I use an earthworks mic (~$600), inexpensive ($150) m-audio mic preamp, and RPlusD software (~$300 with extras) for my measurements but for setting levels often just grab the RS meter because it is fast and easy.