I'm pretty sure they're full. Lots of people have downloaded them in the past. The main problem that I think you are facing is connection timeouts when downloading or listening. Since each file in Shri Guru Granth Sahib album is 41 MB (high quality), it is easy for the server to lose connection.
What I suggest is that, you take a look at the Download Problems section here:
http://sikhsangeet.com/contactus-0-0.htmland use the suggested download managers to download anything from this website. They will help you completely download the file, by resuming when the download breaks.
To make sure that you have the "full" file, check its size when you have it downloaded onto your computer, it should be around 41 MB.
Let me know if you still think they're incomplete and then I'll take a look personally.