Yes, but despite him being a mix, he's not got the build of an app, but more of a knabstrupper.
Knabstruppers are a draft breed and appaloosas are a light breed, bearing no draft resemblances within them whatsoever, so their builds are of course lighter and a touch shorter. They do, however, share the same genetics for appaloosas were bred into the knabstrupper lineage by three stallions, but there are still physical differences seen when you set them side by side. Draft and light.
I work with horse rescue and we have both appaloosa and knabstruppers as well as many other breeds. I simply stated my opinion. You're free to state yours, but in my own opinion Knabstruppers appear to bear cleaner muscle tone and mark where as the appaloosa is a sturdy yet light horse with a more salt or peppered series of marks where Knabstruppers just look like they got rained on by paint rather perfectly. There's less blurring in their marks as there is with appaloosas. All in all, however, they're both beautiful breeds.
note; Oh.. Another thing... Knabstruppers are well known for bearing beautiful flowing manes and tails, too.