Yes the '11/'12 year models only had the ECO setting, similar to post '12 S models. ECO still gives you more aggressive regen when lifting your foot off the accelerator but not as strong as a Leaf with the B mode. Note, with a non B mode Leaf you can still get stronger regen, you just need to lightly put your foot on the brake pedal, don't push too hard or friction brakes will kick in.
The thing with a degraded battery is it won't have the ability to accept regen very much, you may be lucky to get more than a couple bubbles compared to a better battery, very unfortunate as you probably would really like the regen on a degraded battery with limited range. Expect to replace your brake pads more often on a Leaf with a degraded battery.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a