Can the Chattel Mortgage cover after-acquired properties?

General Rule:

No, because Section 7 of Act 1508 provides: A chattel mortgage shall be deemed to cover only the property described therein and not like or substituted property thereafter acquired by the mortgagor and placed in the same depository as the property originally mortgage.

Exception:

Where the after-acquired property is in renewal of, or in substitution for, goods on hand when the mortgage was executed, or is purchased with the proceeds of the sale of such goods. (Torres v. Limjap, G.R. No. 34385, Sept. 21, 1931)