I would maintain that the artwork would be forever changing if you were to revisit that store. However, if this is not the case then you can effectively 'realise' these dreams.

I assume you have a location of reference in your lucid dreams. say, your bedroom? Essentially, an unchanging, usually boring space. Within this, you must have the capacity to summon a door and simultaneously have enough belief to wholeheartedly believe that this comic book store exists beyond it. If you can do this, there is no reason why you couldn't repeatedly visit that store, focus on one of the works, and then wake up with it in your mind.

If, however, you're asserting that you cannot draw nor paint (technique wise), but have seen such creations in your dreams, then I'm afraid it would be irrational to believe you have this refined skill already present in waking life.

The completed, creative piece. Yes you can realise that. But you cannot photographically transfer years worth of drawing/painting technique to waking life because it occurred during a dream.