Coupla things to bear in mind:
Ohms are a unit of impedance, not a measure of output.
An amp's speaker output might be labeled in Ohms, to tell you what load it's looking for.
Speaker cabs often are labeled it Ohms too, to tell you the load they put on an amp driving them.
Second, running an amp that wants a 4 Ohm load into a 16Ω one instead might not be ideal.
In general, a lower load than spec'd is more likely to cause problems, but occasionally a higher load can, too.
How loud you play is an important factor here. At bedroom volumes, trouble is unlikely in either case.
But if the amp is being pushed hard and for long periods, improper loading is more likely to cause trouble.
The transformers in many amps - especially those made overseas, like the modern Fenders - aren't typically very robust.
You might check with somebody who knows this model pretty well before pushing it hard with a 16Ω load.
Could be perfectly okay. But if it were mine, I'd want to make sure.
I probably wouldn't run my blackface Bandmaster into a 16 Ohm load. Not at stage volume, anyway.
