I can confirm 100% that it is only the magazines. I live in a state with a weird magazine ban (MD). Most states with a ban, ban possession of mags over a certain round count (usually 10 rounds, though NY tried to make it 7 a few years back). Here in MD we are allowed to own any mag we want, we just can't buy, sell, trade or give away magazines with greater than 10 rounds within the state. However, we are free to go to other states to buy standard capacity mags. It is a quite common practice in MD to buy a gun with a neutered 10 round mag at home then drive to VA, WV, PA or DE to buy standard capacity mags. Of course, there is a bill in the state legislature just about every year to make it a ban on possession, but so far they've failed (it's MD, eventually it will pass, I just hope I'm out of here before then).
Personally I have four guns I bought since the ban with at least one standard capacity mag, and another from the Federal ban years ago. All three of my compact CZs (CZ P01, CZ 75 Compact, and a CZ PCR) have been bought within the past 2 or 3 years and I have two of the older 14 round compact mags and two of the newer 15 round mags. I also have a S&W M&P40c with a 15 round mag (with sleeve since it is a compact that takes 10 round mags standard), and I have a 15 year old (plus or minus a couple years) CZ 75B bought during the federal ban with one or two 15 round mags (I usually only take the gun to the range with the one mag in the gun, I'll have to check my spare mags), and I'll likely pick up one of the newer 16 round mags next time I'm at a gunshow in PA or VA. So far, all of my standard capacity mags have been bought in VA (except for the 15 round mag on the CZ 75B which was bought when I could still legally buy them in MD).
They do the mags the same way they did during the federal ban years back. Dimples or other modification of the mag body or follower (or both). They don't change the gun. Enough states have 10 round restrictions that there is still a financial incentive for magazine makers to continue making the neutered mags, and no state requires a modification to the gun.
My guess, they were over stock on the 10 round version and put it on sale to move the excess inventory. I see your post is 11 days old, I'm sure the sale is over. I hope you moved on the CZ on time. If not, next time you see such a sale, buy with confidence that you'll be able to get regular mags after you buy the gun.
Edit:
I only read about half the posts when I made mine. I see you went ahead and bought the gun. I'm glad you got it on time to get the discount! You'll love your new CZ!