Mike said approx. 0.5" wider, so if you have one of the older ones you can work out what that will mean.
I also get the impression that lapel width was standardized across sizes, but maybe there is some variation on the extreme ends. I seem to recall my lapels measuring 2.75" on my size 34s and that being the same for the larger sizes as well. Hopefully Mike can chime in and let us know.