About 130 stores are being closed over the next 5 years. That was announced months ago. There were articles in the Wall Street Journal, etc. Most of the other stores are being remodeled over the next 5 years.
As far as is everything on sale - no. The stuff that is 75% off today was marked down to 50% about 2 weeks ago. Now we have other things marked down to 25-50% off. The majority of merchandise in the stores is at regular price. It seems to me (and this is JUST my observation) that in the past year, new product lines seem to come in faster and faster so consequently there are more sales to make room for the new stuff.
As far as returning stuff that is now on sale for credit - it depends on when you purchased it. Your best bet is to call that store directly. There is a good chance the thing you purchased at 50% off isn't there anymore.
I went over to our store at lunch and except for the few plush items that are marked down to 75%, most everything else is gone. The CMs said when the store opened, people poured in and grabbed it all up quickly. Last night we had lots but it is mostly gone now.