I believe all 335d have Brembo front calipers, but the standards are silver. It might just be the picture but that blue looks different to mine (my blue looks a little “flatter” I think) so I suspect someone may have just painted the standard 340/330 (IIRC) caliper setup on your car?
edit - from when I was looking for what options I wanted to buy
standard brakes = 340mm front, silver Brembo 4-pot caliper. 330mm rear, silver single-piston caliper.
M-Sport brakes = 340/370mm front, blue Brembo 4-pot caliper (same caliper for both sizes, but different mounting so you can't upgrade from 340 to 370). 345mm rear, blue two-pot Brembo caliper.
M-Poerformance brakes = same as sport, but in three different colours (red/orange/something else)
The picture of your rear caliper also doesn't look like what I remember the Brembo rear caliper looking like (although I haven't been out to look at the one on my car to compare) which again makes me think you've got a stock 340/330 setup that used to be silver but has been painted blue to look like the M-Sport because the front caliper is the same one so if you got the colour on it, it would look the part.
There's also
https://www.mdecoder.com/ where you can throw in your VIN and see the spec sheet; if you see "S2NH (M Sport Brake)" then 340/370 front, 345 rear. If not, then 340/330.