How euphemistic is 傢伙? 傢伙 (an example of a Chinese lexeme that does not map bijectively between simplified and traditional characters, the simplified word being 家伙) is translated, in the only translation Wang Xiaobo's work has received to date, as 'tool.' Which would indicate that the word is a euphemism (委婉语) for penis in the following.

从派出所到居委会，都认为他是个好贼，舍不得送他进监狱，只可惜他偷得太多，最后只好把他枪毙掉，这使派出所的警察和居委会的老大妈一齐掉眼泪。这个贼临死还留下遗嘱，把尸体捐给医院了。我有个同学考上了医科大学，常在福尔马林槽里看到他。他说，那位贼兄的家伙特别大，躺在水槽里仪表堂堂，丝毫也看不出是个贼，虽然后脑勺上挨了一枪，但不翻身也看不出来。

— 2015 by 王小波.
But how euphemistic?
Because the English word 'tool', while euphemistic, is also a bit cheeky. It's even an insult. It's not detached, scientific-sounding, or fantastical, like other euphemisms for things.
Does 傢伙 carry those nuances? (I have to admit, it sounds just a bit scientific-sounding and detached to me. But obviously I'm not a native speaker.)
In other words, has the pair of translators captured something of a nuance here? Or has meaning been added, or lost?
I don't know the nuance carried the English word "tool". But according to your description, I don't think there's such nuance in Wang's article. It is just a normal euphemism, with no added meaning to the original word (penis).

Basically, 傢伙 would carry a similar connotation as "manhood" or "member" (maybe without the informality associated with "member").