借金 and 貸出: borrowed money and lending
Distinguish money owed by a borrower from a lending procedure.
The borrower of money
借金 (しゃっきん) means borrowing money or the resulting debt. 「借金を返しました」 says that borrowed money was repaid. Returning a borrowed book is not normally called 借金.
「借金がありません」 means having no debt. It does not mean having no money or never having borrowed any object.
A lending procedure
貸出 (かしだし) means lending items or money. 「図書館の本の貸出は五冊までです」 says that library loans are limited to five books. It applies to lending services for books, not only monetary debt.
「貸出の手続きをします」 means carrying out the lending procedure. Check the subject to determine whether it describes a borrower's action or a staff member's processing.
The notice's perspective
「この本は貸出中です」 says that the book is currently on loan to someone. It does not promise that a reader can borrow it immediately. Separate the lending service's status from a user's borrowing action.
「貸出中の本を予約しました」 means reserving a book currently on loan. It does not say that the speaker has already received and begun reading it.
Does 「貸出期間は二週間です」 necessarily refer to repaying money?
Show the answer and why
No. It gives a two-week loan period and may be a library-book notice. Check what is being lent.