Becareful not to open yourself up to undue scrutiny by playing dress-ups.
I would suggest not wearing uniform and definitely do not wear epilettes unless they are part/parcel of your current job (even then Id consider the implications carefully)
If I was flying your check, I would most definitely ask you about the meaning of any epilettes you were wearing. If your answer was simply that it seemed like a good idea at the time, I would honestly wonder what was going on in your head.
Wear something smart/tidy from your current wardrobe. If you can muster up some dark trousers and a white shirt, fantastic, but a blue shirt fits the bill too.
You may find that wearing an unfamiliar 'uniform' could even unsettle you (wondering what people think etc). This will have an adverse effect on your flying performance too!
If others are in uniforms and youre not, just joke about it...."wow, you guys have a uniform? in my tinpot outfit its just jeans and t-shirts.....it was a chaos just trying to find something to wear today that wasnt covered in dust!"
That shows a lot more class/character than some obviously shiny new uniform. Dont be a wannabee, let them see that you have something they want.
ps: Polish your shoes and dont wear silly socks! Make sure they match your shoes & belt. Otherwise you just look like a used car salesman with a pocket protector and comb-over.
Be yourself.