I do not know if there is a way to get this information using RESTful API but you can get a list of all the attributes for a model or model type using the Command Line Interface (CLI) "show attributes" command.
For a model type you need to supply the model type handle and enter the command as follows (this example is model type 0x3d0002 which is the GnSNMPDev model type):
> ./show attributes mth=0x3d0002
Id Name Type Flags
0x10000 Modeltype_Name Text String R,S,M
0x10001 Modeltype_Handle Modeltype Handle R,S,M
0x10004 Contact_Status Integer R,W,G,M,D,L
0x10009 Security_String Text String R,W,O,M,D
0x1000a Condition Integer R,W,G,M,D
0x1000b Condition_Value Integer R,W,G,M
0x1000c Value_When_Yellow Integer R,W,V,M,D
0x1000d Value_When_Orange Integer R,W,V,M,D
0x1000e Value_When_Red Integer R,W,V,M,D
0x1000f Composite_Condition Integer R,W,G,M
0x10010 Yellow_Threshold Integer R,W,G,V,M,D
.
.
.
For a specific model you need to supply the model handle of the model (for this example, the model handle is for a Cisco 7606 router modeled using the Rtr_Cisco model type:
> ./show attributes mh=0x4001d0 | more
Id Name Iid Value
0x10000 Modeltype_Name Rtr_Cisco
0x10001 Modeltype_Handle 0x21000c
0x10004 Contact_Status 1
0x10009 Security_String
0x1000a Condition 0
.
.
.
Joe