I spent some time today mixing and matching some ligatures and caps to 
a Guardala Laser Cut Tenor Mouthpieces.   

The older WW&BW ones with the metal ligs came with a cap with "DG" on 
the end.  This set is virtually identical with the cap and lig 
supplied with metal Dukoffs.  The Dukoff cap I have here has a "D" on 
the end and a couple of vent holes.  The ligs are the same except for 
plating. 

The Selmer metal alto 402 ligature does fit.  But it is tight when new 
and you need to "train" it to fit.  You need to bend the sides in 
closer to the body of the mouthpiece.  A Rovner cap will not stay on 
this slim-fitting lig.  Something like a Runyon cap from a 
Quantum/Smoothbore/XL/Jag probably would.  But I I do not have one 
here to try.

Rovner trivia:  It appears the cap size is "stamped" inside the end of 
the cap backwards.  Actually it is probably to keep track of the 
injection molds.  

Also, a BG metal lig, L28MJ, fits the Guardala.  It is a two rail reed 
contact ligature.  It is somewhat unusual in that the metal band of 
the lig is made so that it only touches at the top of the mouthpiece 
and the reed.  The sides are otherwise spaced away from the mouthpiece 
ind of like a Winslow.  It also has a reverse thread screw that stays 
ceterd as it tightens, like a Vandoren Optimum does.