Is a guarantor obligated to pay on a guaranty in gold coin even if the guaranty does not specify this means?

[189 Cal.App.3d 1506] First Nat. Bank v. Spalding (1918) 177 Cal. 217, 170 P. 407, holding the guaranty must be construed together with the note to determine the parties' intent, observes: "While it is true that a ... guarantor may stand upon the strict terms of his contract, this means merely that his liability is not to be extended by implication beyond the express terms of the instrument in which his guaranty is contained." (At p. 221, 170 P. 407.) The court held the guarantor was bound to make payment on the guaranty in gold coin, even though the guaranty did not specify this means of payment, because the notes provided for such payment. (Id., at pp. 221-222, 170 P. 407.) Additionally, the guarantor was obligated to pay as attorneys' fees a certain percentage of the unpaid balance on the notes, as specified in the notes, although the guaranty only called for payment of a "reasonable" fee. (Ibid.)