No, you would not have had 40 oz of water in that case. The reason is that when ice melts, it undergoes a phase change from a solid to a liquid, but its mass remains the same. Therefore, when the ice melts, the resulting water will have the same mass as the original ice.
However, the volume of the water will be slightly less than the volume of the ice. This is because water expands when it freezes, which means the solid ice occupies more space than the liquid water it turns into. So when the ice melts, it will occupy a smaller volume as liquid water compared to its original volume as ice.
Since you initially filled the 40 oz water bottle with ice to the brim and then added water, the total volume of ice and water combined would be greater than 40 oz. When you consume all the water and then consume all the melted ice, you would have consumed a volume less than the original 40 oz, due to the decrease in volume caused by the ice melting.