You can buy cheap old watches from Romania with Molnija 3602 movement inside from eBay at around 50$ shipped.
The transplant is not that hard to do.
The main problem is that if you got a 6154 from River or somebody else it's most likely fitted with an asian6497 and the cannon pin from the Molnija and the 6497 are different and the hands won't fit.
What you'll have to do is cut the part that fit around the canon pin from your Romanian hands and glue it nicely under the 6154 hands.
The caliber of the Molnija is slightly smaller from the 6154, so you'll also have to fit a movement ring of 0.5mm, I used a very small wire.
And here's the result:
