When Commander Riker and Lt. Yar are performing repairs on the bridge of the Enterprise-C, Tasha refers to Geordi as Lieutenant. We could assume here that in this time line LaForge had not been promoted to the rank of Lieutenant Commander. However, in later scenes, particularly the Ready Room briefing, it is clear that Geordi is wearing the rank of Lieutenant Commander.
When Dr. Crusher taps her badge and calls for transportation for herself and Captain Garrett, she puts her tricorder away and reaches up to tap her badge again. She visibly catches herself, and appears embarrassed at the slip.
At the final scene of the episode when Guinan asks Geordi about Tasha, you can see LaVar Burton is still wearing the uniform from the alternate time line, it's most noticeable from the end of the sleeves which has black wrists.
Just before the Enterprise-C enters the rift to go back to their time 22 years previous, the Enterprise-D is taking fire from the Klingons. A dark bar indicative of a dolly arm shadow can be seen passing from port to starboard on the Enterprise's surface.
Captain Picard is stunned to hear that children should be on the Enterprise. But Wesley is still part of the crew in the alternate time line, although he was only on the Enterprise as a family member to begin with. Then again, it is possible that because of wartime, he may have had a quicker Academy education and been officially transferred onto the Enterprise as a junior officer. This is borne out by the fact that Wesley is wearing a full Ensign's uniform in Command red, rather than his Acting Ensign's "uniform" as seen in the unchanged time line.
When Tasha Yar joins the Enterprise-C crew, she is still wearing her communicator and phaser from the alternate reality Enterprise-D. This would result technology being taken back to the time line of the Enterprise-C, and the battle with the Romulans and this risk of the technology falling into their hands. Picard made it clear that no technology from the Enterprise-D time line should go back with the Enterprise-C.
After Captain Garrett's death, Lieutenant Castillo assumes command of Enterprise-C, but he continues to be called "Lieutenant." Certain 20th Century maritime traditions have changed in the 'Star Trek' universe, however, this tradition, which probably dates back more than 1,000 years, will not change. Loyalty to their former commander notwithstanding, the second Castillo assumes command, he is the Captain in role and, regardless of actual rank, he would be addressed as "Captain" by everyone - especially naval officers in a war zone.
In the final scene where Guinan and LaForge are having a drink and conversation about Tasha Yar, LaForge is clearly wearing the uniform from the alternate reality. This is identified with the black cuffs on the sleeves and the altered collar.