Garde Ulanen Regt. Nr. 3.... regimental distinction appears to be YELLOW. Officer's litzen probably silver.
Image of an NCO's uniform from Garde Uhlan Regt (number unknown) in 1915 Field Grey with Red as the regimental distinction. . Officer's similar... better cut.... better quality cloth.... different shoulder boards, litzen in gold not yellow:
http://www.germanmilitaria.com/imperial/photos/G016269.htmlFound coloured illustration of Officer from Garde Ulanen Regt Nr 1 wearing M1915 feldbluse... no piping or decoration anywhere but also wearing Officers visored cap with red band on crown (regimental distinction) and red piping around the edge of the top of the cap. Photos from link above may also be from Garde Ulanen Regt Nr 1.
This is fun........