It is unlikely that the Drake Salt Works were guarded by any Texas cavalrymen. All of those regiments were with Taylor's army on the south side of Red River during this portion of the campaign. The units you mention did join Taylor as described, but they remained south of the river. After the opposing armies reached Alexandria, Taylor did detach one Texas regiment to reinforce Liddell's (later Harrison's) force near Pineville. This was long after the "skirmish" at Bayou Saline or Salisbury Bridge. You mention "items found by locals." Are you referring to bullets or artillery projectiles found by local relic hunters? These might be interpreted as signs of a skirmish, but might also simply be items dropped by soldiers. Although the effort might not be worth the trouble involved, your best bet might be to try to find letters, diaries, memoirs, etc. by men who served in the 2nd New York Veteran Cavalry Regiment to see if they make any mention of their skirmish.