The metal mesh you found in the corners are Corner - Rite's & were used in conjunction with Rock Lath & Plaster.
If you look at a cross section if it is Rock Lath you would see 3/8" Gypsum board (looks like sheet rock) than a 3/8" Gypsum Plaster base applied over the Rock Lath, next coat would be a thin white coat of Lime Plaster about 1/8" thick.
Yes there is a product that can be applied over a painted Plaster surface.
It is Master of Plaster high cost for material but well worth the money for a smooth finish.
If you look at a cross section if it is Rock Lath you would see 3/8" Gypsum board (looks like sheet rock) than a 3/8" Gypsum Plaster base applied over the Rock Lath, next coat would be a thin white coat of Lime Plaster about 1/8" thick.
Yes there is a product that can be applied over a painted Plaster surface.
It is Master of Plaster high cost for material but well worth the money for a smooth finish.