Sea Level in Paleogeographic Maps
There are various plate tectonic models around, that are able to provide insight in paleobathymetry and -altimetry. These models include information on sea floor spreading and subduction, which provides much information on bathymetry. Also plate tectonic movement largely drives the uplift of mountain ranges, and combining this with isostatic effects of sediment loading, glaciation, etc. you can get a fair picture of paleoaltimetry as well. Of course this method provides only relatively low resolution data, and to get more detailed maps you need more localised data.

Outcrops and bore holes provide much information on the depositional environment, and for example sequence stratigraphy is a tool that can be used to predict/retrodict regional environments. If you know from a number of locations where the coastline was relative to its current position, and know from models etc. where the sampling locations were in the past you can map paleocoastlines as well. 

So to answer your question shortly, yes there is a lot of global information available by combining large scale models and local investigations, and where such information is missing you can at least provide an educated guess of coastal positions.