Latex paint on any leather item can be removed fairly easily. Latex has a rubber base, so it sits on top of the leather like a stamp on a letter. The challenge is to loosen its grip.
Apply a warm-water compress to the paint using a face cloth or piece of cheesecloth. This will soften the paint and loosen its grip on the leather. Try to gently peel away the paint. Do not scrub.
Apply a leather cleaning system typically available from furniture retailers. It should include two bottles: a colorless cleaner and a conditioner. Valspar Guardsman is one example. Follow the manufacturer's instructions for the cleaner. It contains mild concentrations of several organic solvents; these in concert will loosen the grip of the latex paint without removing the color of the leather.
Apply the conditioner per the manufacturer's instructions. The leather will likely appear dulled after Step 2, but the conditioner will restore the luster and blend it with the rest of the item.
Rub the paint and surrounding leather with a cream-based leather conditioner. With luck, this will soften the paint and it will begin to peel off. Use a soft cloth, like cheesecloth, and do not rub vigorously--you will damage the surface of the leather.
Point a hair dryer, set to low heat, at the paint stain for 45 seconds if the above step does not work. Attempt to lift a corner of the paint stain as you would try to peel a label from a bottle. Point the dryer between the paint and the leather as you peel away the paint.
Soften the paint with thinner if the above step do not work. With a small paintbrush or cotton swab, brush the paint with enough thinner to soften but not soak the paint. Repeat the procedures for wet paint. Do not touch the leather with the liquid--it may remove color.
Recondition your leather with a cream-based conditioner or saddle soap. The leather will be dry after your repair and perhaps dull, but not permanently damaged.