The stock and the grip look a bit like this gun
, although finding a replica might be tough.
For the bow- if you got a 4' long aluminum bar, 1/8" thick and 2" wide, you could try to find some pillars or something to bend it around. Wouldn't be as thick as what's pictured, but it would be sturdy and wouldn't require you to do much work in your apartment. Also you could do the bending in a few minutes. Hardest part would be making sure it's 100% symmetrical.
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