Outlined Specular shader?

I have an outlined Diffuse shader based on the one found here:

 Shader "Outlined/Diffuse (line width based on depth)" {
     Properties {
         _Color ("Main Color", Color) = (.5,.5,.5,1)
         _OutlineColor ("Outline Color", Color) = (0,0,0,1)
         _Outline ("Outline width", Range (.002, 0.5)) = .005
         _MainTex ("Base (RGB)", 2D) = "white" { }
     }
     
 CGINCLUDE
 #include "UnityCG.cginc"
 
 struct appdata {
     float4 vertex : POSITION;
     float3 normal : NORMAL;
 };
 
 struct v2f {
     float4 pos : POSITION;
     float4 color : COLOR;
 };
 
 uniform float _Outline;
 uniform float4 _OutlineColor;
 
 v2f vert(appdata v) {
     // just make a copy of incoming vertex data but scaled according to normal direction
     v2f o;
     o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
 
     float3 norm   = mul ((float3x3)UNITY_MATRIX_IT_MV, v.normal);
     float2 offset = TransformViewToProjection(norm.xy);
 
     o.pos.xy += offset * _Outline;
     o.color = _OutlineColor;
     return o;
 }
 ENDCG
 
     SubShader {
         //Tags {"Queue" = "Geometry+100" }
 CGPROGRAM
 #pragma surface surf Lambert
 
 sampler2D _MainTex;
 fixed4 _Color;
 
 struct Input {
     float2 uv_MainTex;
 };
 
 void surf (Input IN, inout SurfaceOutput o) {
     fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
     o.Albedo = c.rgb;
     o.Alpha = c.a;
 }
 ENDCG
 
         // note that a vertex shader is specified here but its using the one above
         Pass {
             Name "OUTLINE"
             Tags { "LightMode" = "Always" }
             Cull Front
             ZWrite On
             ColorMask RGB
             Blend SrcAlpha OneMinusSrcAlpha
             //Offset 50,50
 
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
             half4 frag(v2f i) :COLOR { return i.color; }
             ENDCG
         }
     }
     
     SubShader {
 CGPROGRAM
 #pragma surface surf Lambert
 
 sampler2D _MainTex;
 fixed4 _Color;
 
 struct Input {
     float2 uv_MainTex;
 };
 
 void surf (Input IN, inout SurfaceOutput o) {
     fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
     o.Albedo = c.rgb;
     o.Alpha = c.a;
 }
 ENDCG
 
         Pass {
             Name "OUTLINE"
             Tags { "LightMode" = "Always" }
             Cull Front
             ZWrite On
             ColorMask RGB
             Blend SrcAlpha OneMinusSrcAlpha
 
             CGPROGRAM
             #pragma vertex vert
             #pragma exclude_renderers gles xbox360 ps3
             ENDCG
             SetTexture [_MainTex] { combine primary }
         }
     }
     
     Fallback "Diffuse"
 }

I've tried to combine it with the source of the builtin Specular shader to create a similar Outline shader that's based on Specular instead of Diffuse. However I have not succeeded, because I'm not very familiar with ShaderLab. What parts of the code do I have to edit to make it Specular?