Whats your views on pups with not the best rear angulation, can they improve with age?

I was looking at a Parsons Terrier pup a our ringcraft class recently with not the best rear angulation and topline.
Due to it been a bit straight in the rear makes its topline slightly high at the rear, you can level the topline by over stretching.

I was thinking if its angulation improved with age, it would make a good show dog.

Many puppies will be bum high as the different bones often mature at different rates.  Rears especially seem to go through a straight stage and then the bend of stifle comes back if it was there to start with.

http://www.provet.co.uk/health/diagnostics/growthplatedogs.htm

This chart is more helpful: https://gordonsetterexpert.files.wordpress.com/2015/02/growth-rate-closure-diagram.jpg

The age of the pup is 6 months.

Thanks Barbara, I did ask the owner if they had any pics of the pup at 8 weeks old to see if its bend of stifle was there then. They didnt, nice pup I hope it dose improve.

In all the breeds I've been involved with..rears improve most in angulation, they 'Let down behind'
but..if they are overangulated as puppies they usually become cow hocked and over reach or crab on the move.

I agree, in the main the fronts (shoulders) need to be there from the start other than them going through a narrow stage and then broadening out, but the rears can go really straight and then drop again, more in some breeds than others.  Seems to be quite noticeable in Gordon Setters fro example.