Pivot Works does'nt list the 79,but there's a slight chance they might have something that'll work.
If you have a local bearing shop near by,they should be able to get you what you need....just bring them the old bearings to be sure you get an exact fit.
There's a company next door to me called Capeway Bearing here in Plymouth,MA...they've been there for 25+years.They have every bearing for all my bikes and sleds.There's been times when I need an odd-ball one for something else,and if they don't have it,they'll make it right there on site usually in a day.