Actually, that is not true. Usually during a quest when you have to craft some special thing (such as a craft used only the quest, and disappears after being completed) you have the possibility to craft 2, if you do it in both forge or workshop. Some ppl like me does it often and we keep the second craft as a souvenir in our inventory. I have a lot of useless things like this.
Also, in some quests you have the ability to craft 2 of the main rewards, such as 2 of Lady griseldas statue and car.
So, try always to craft 2 things