This is the last ThinkPad with the old keyboard, before they introduced the chicklet style. Of course, the backlighting they got with the new keyboard of the T530 was nice, and the replacement of the page up / pagedown / escape keys was debated, but the spacing between the keys and the lower quality was a turn off for most people.

Source: lenovo thinkpad t520 | eBay

Of course the T530 keyboard was built in different qualities:

“New FRU for keyboard that is great:  04W3063
Old FRU of keyboard that was lousy:  04W3137

It’s also easy to tell which one you have – remove the trackpoint cap:

04W3063 = yellow under trackpoint
04W3137 = blue under trackpoint”

from https://forums.lenovo.com/t5/T400-T500-and-newer-T-series/Thinkpad-T520-vs-T530-keyboard/td-p/787997/page/2

One way to improve your T520 is to upgrade the screen for under $100,- to full HD

https://www.ifixit.com/Guide/Upgrading+the+Lenovo+ThinkPad+T520+Display/9763

And there is a way to get the T520 keyboard onto a T530. You can remap a lot of the keys and get quite a way, but not all the way…

http://www.thinkwiki.org/wiki/Install_Classic_Keyboard_on_xx30_Series_ThinkPads

Good luck!