Hello Balazs Garai
The excellent stkz database from LEMB
http://www.luftwaffe-experten.org/stam-g.html indicates that GA+LE was an E-7 with W.Nr. 3803 and served with JFS 4 JG 102.
For JFS 4 info look here:
http://www.ww2.dk/air/schule/jfs4.htm
For JG 102 info look here:
http://www.ww2.dk/air/jagd/jg102.html
I have Bf 109 E-7 GA+HP a picture that is from an ex-eBay auction which might give you a good idea of what your Grandfather's plane looked like: