While alembic support has finally been added to 3dsMax 2015 the maxscript documentation has yet to appear. With a bit of digging around this is what I have found.

Alembic Objects

selecting an object and using showproperties $ show these properties

 .source : filename
.object : string

Importing alembic files

files are imported using the ImportFile command. You can show a list of supported plugins by using:

 print importerPlugin.classes 

This will list Alembic_Import as a plugin class

 showInterfaces Alembic_Import 

Will show the following

Interface: AlembicImport
Properties:
.ZUp : boolean : Read|Write
.ImportToRoot : boolean : Read|Write
Methods:
Actions:

Interestingly while ImportToRoot IS included in the standard max dialog ZUP is not, and alas I cannot find a way to switch the time range options using max script.

Exporting alembic files

the exporter can be inspected in a similar way

 print exporterPlugin.classes 

This will list ABCEXP as a plugin class

 showInterfaces ABCEXP 

Will show the following

 

  Interface: AlembicExport
   Properties:
    .CoordinateSystem : enum : Read|Write
       CoordinateSystem enums: {#Max|#Maya}
    .ArchiveType : enum : Read|Write
       ArchiveType enums: {#HDF5|#Ogawa}
   Methods:
   Actions:

Again its not obvious how to access the time cache range shown in the Alembic Export dialog