737-600 Seating capacity question ???

I know there is already another thread on this topic, but it is quite long and I just have a relatively straightforward question to ask.

The maximum seating capacity for the 737-600 in Aspern has now been changed to 132 from 149. I assume that airlines which already have higher density configurations for that aircraft can of course continue to fly their planes with those configurations, HOWEVER, it appears to me that airlines who had the 737-600's before the change are still able to apply the old higher density configurations to new aircraft that have been purchased after the change. Is this correct ?

So for example, because I did not have the 737-600 before the change and had not created a seating configuration for it, if I bought one now, the maximum seats I could have in that aircraft would be 132. However, another airline, who had purchased and/or created a seating configuration for the 737-600 before the change would be able to purchase a new 737-600 aircraft now and be able to have up to 149 seats in it.